426 CLINICAL APPLIED ANATOMY. 



both. The urinary tubules become directly infected from the 

 calyces into which they open. Ascending infections are gener- 

 ally suppurative, and occur in connexion with urethral strictures, 

 prostatic enlargements, and infections of the lower urinary 

 passages. 



The kidney is occasionally infected by the lymphatic route. 

 The lymphatics of the ureter communicate directly with the 

 lymphatics which lie between the urinary tubules. Hence 

 infection can travel from the urinary bladder along the lymphatics 

 of the ureter to the kidney. Extension by this track explains 

 those cases in which the renal cortex is alone involved, the 

 pyramids and pelvis remaining free. 



Tuberculosis of the kidney may be the consequence of 

 infection carried to the organ by the blood stream or reaching it 

 along the ureter, the ureteric lymphatics, or from structures with 

 which the organ lies in direct contact. 



In miliary tuberculosis the tubercles are widespread and 

 originate in the small vessels. But tubercle bacilli brought to 

 the kidney may be excreted and may find a nidus in the glomeruli 

 or tubules during this process ; a chronic renal excretion tuber- 

 culosis may originate in this way. Presumably the number of 

 organisms carried to the kidney in such cases is not very great. 

 In the earlier stages of excretion tuberculosis the cortex is mainly 

 involved. 



When infection ascends the ureter from below it naturally tends 

 to attack and erode the lower parts of the pelvis first, spreading 

 to other parts of the kidney later. Occasionally infection appears 

 to ascend the lymphatics which accompany the ureter and in such 

 cases the pelvis may at first escape. 



The kidney has been known to be directly infected by a sub- 

 jacent psoas abscess. The direct anatomical connexion of the 

 kidneys, ureters, bladder, prostate, vesiculse seminales and 

 epididymis has much influence in determining the distribution of 

 tuberculous lesions, and particular attention should be paid to all 

 these structures when investigating a case of renal tuberculosis. 



The tuberculous thickening of the ureter can sometimes be 



